- please use "Requires: python-pycrypto" instead of the if-switch

- please use "%python_expand %fdupes %{buildroot}%{$python_sitelib}" instead of the two entries
or just simply: %fdupes %{buildroot}%{_prefix}
(you don't need slash between %buildroot and %sitelib or %_prefix or any of these

- please run tests for all python versions: "%python_exec -m nose" instead of just "nosetests"

thanks for your hints, have had some doubts regarding "Requires", but it seems there is some magic ...